The invention pertains to reciprocating conveyors, and more specifically, to reciprocating conveyors which provide sequential movement of a load thereon by simultaneous movement of all of the slats in the load conveying direction, and sequential return of the plurality of slat groups.
Reciprocating conveyors providing continuous movement are generally known in the art. U.S. Pat. No. 4,580,678, issued to Foster, discloses a reciprocating floor conveyor system in which a group of six floor slat members, staggered in a position relative to each other, are each first advanced and then sequentially returned such that five slats are moving forwardly while one slat moves in the return direction. The Foster reciprocating floor conveyor requires two separate sources of hydraulic pressure, one for advancing the floor slat members and another for retracting the floor slat members. This requirement for two separate hydraulic pressure sources increases the cost and complexity of the mechanism. The reciprocating floor conveyor of Foster does not provide hydraulic flow of a constant rate, regardless of flow pressure, to each individual slat. Thus, if some slats experience a greater load than others, the slats experiencing this greater load will move a lesser distance than the slats experiencing a lesser load, or not at all, and the sequential advance of the slats will be disrupted due to this lack of substantially constant flow rate in the respective hydraulic lines.
U.S. Pat. No. 4,144,963, issued to Hallstrom, discloses a reciprocating conveyor in which at least three elongate slats are employed such that there are always a greater number of slats moving simultaneously in a conveying direction than the number of slats moving in the opposite direction. In order to achieve the above slat movement, the Hallstrom patent requires a complex fluid pressure control valve having relatively movable first and second valve members. The first valve member has a plurality of first passageways each communicating with a different extensible fluid pressure cylinder. The second valve member has a common second passageway communicating simultaneously with more than half of the first passageways, and a third passageway communicating with the remaining first passageway. One of the first valve member and the second valve member is moved relative to the other to communicate the second and third passageway selectively with different ones of the first passageways. In addition to the above unduly complex fluid pressure control valve, the Hallstrom patent is also limited by the fact that, like the above Foster patent, substantially constant flow rate, regardless of flow pressure, is not provided. Thus, as stated above, the presence of unequal loads on respective slats will cause disproportionate slat movement resulting in disruption of the slat sequence.
U.S. Pat. No. 3,534,875 discloses a slat conveyor having three groups of slats, two of which move simultaneously in a load-conveying direction, while at the same time, the third group moves in the opposite direction to provide continuous movement.
In U.S. Pat. Nos. 4,143,760 and 4,611,708, three groups of slats all move simultaneously in a first load conveying direction and then each individual group moves sequentially in the opposite direction to cause sequential load movement. U.S. Pat. No. 4,856,645 teaches a slat conveyor having a group of non-moving "dead" slats spaced between two groups of slats that move simultaneously in a load conveying first direction and sequentially in an opposite direction for sequential load movement.
U.S. Pat. No. 4,157,761 discloses a discharge mechanism for discharging particulate loads that includes first and second stoker rods each having a plurality of cross bars. A fixed floor angle is located between each of the cross bars. The first and second stoker rods reciprocate lengthwise, rapidly, and, at the same time but out of phase.
U.S. Pat. Nos. 4,492,303; 4,679,686; 4,749,075; and 4,785,929 all issued to Foster disclose various components for reciprocating floor conveyors including hold-down members, bearing systems, and drive/guide systems.
U.S. Pat. No. 5,222,593 issued to Quaeck discloses a reciprocating floor conveyor in which a timing cylinder of smaller displacement coordinates the reciprocation of the slats. While this system functions well, the requirement for cylinders of two different sizes adds a degree of complexity.
A need thus exists for a reciprocating floor conveyor able to sequentially move heavy loads of, for example, one million pounds or more.
A need exists for the above type of reciprocating floor conveyor in which the slats are engaged, but slidable, to prevent passage of the particulate load matter therebetween.
A need exists for the above type of reciprocating floor conveyor in which adjacent slat members are oriented at different elevations above the conveyor floor to facilitate adjacent slat engagement.
A need exists for the above type of reciprocating floor conveyor in which each group of slat members is controlled by a separate timing slat that has a surface area larger than the other slat members in the group.